The goal of this Small Business Innovation Research project is to demonstrate a fluorescent glucose-indicator chemistry with high thermal stability for construction of an in situ optical glucose sensor to monitor the culture medium of continuous process bioreactors. The specific binding properties. The new polymer will be evaluated for use in a competitive binding glucose assay using fluorescence resonance energy transfer quenching to detect glucose levels in the culture medium. The evaluation will include characterization of the glucose binding polymer for molecular weight and composition and spectrofluorimetric titration of the proposed indicator chemistry with glucose and known culture medium analytes and metabolites. Spectral data will be examined for glucose sensitivity and selectivity over significant reactor concentration ranges. An in situ glucose probe would improve the ability to control the physiological state of glucose substrate reactors while reducing the cost and complexity. The probe would also provide the type of real time glucose concentrations necessary for substrate limiting culture operation. Improvements in bioreactor performance will aid the ongoing efforts to develop new drugs and therapeutic proteins using biotechnology. PROPOSED COMMERCIAL APPLICATION: Success in the applications of modern biotechnological techniques is evidenced by the variety of products, ranging from specialty chemicals, polymers and food, to therapeutic drugs produced by using recombinant DNA methodologies in various cell culture systems. There is constant need to develop and implement a new sensing system to effectively control and optimize these biological processes.